As known, a rapid prototyping (RP) technology is developed from the concepts of forming a pyramid by stacking layers, and the main technical feature is to achieve fast formation. A complicated design can be transformed into a three-dimensional physical model automatically and fast without any cutting tools, molds and fixtures. Thus, the development cycle of new products and research and development cost are largely reduced to ensure the time to market for new products and the first-time-right ratio. Accordingly, a complete and convenient product design tool is provided between technicians and non-technicians (e.g. managers and users), and the product competitiveness and the quick reaction capability of enterprises in the market are improved obviously.
Recently, the rapid prototyping technology develops a method for producing three-dimensional physical models by combining jet printing and precise positioning of carriers. The producing method begins by first spreading a layer of powder on the carrier and then printing high viscosity liquid binder on part of the powder by using jet printing technology, so that the liquid binder and the powder stick together to become solidified. After the above steps are repeatedly done, a three-dimensional physical model is produced by stacking multiple layers.
Since the processes of spreading powder, printing and taking out the finished product are manually performed according to the conventional rapid prototyping technology, the flying dust usually pollutes the working environment and contaminates the whole three-dimensional rapid prototyping apparatus. For maintaining normal operation, a dust-collecting and cleaning task is manually done after a specified stage of the rapid prototyping technology. However, during the cleaning process, the finished product is possibly destroyed or the components of the rapid prototyping apparatus are possibly damaged because of carelessness. Moreover, the increased frequency of performing the cleaning process is labor-intensive, time-consuming and costly. If the frequency of performing the cleaning process decreases, the dust pollution problem cannot be effectively solved.
Another rapid prototyping technology will be illustrated with reference to FIG. 1. FIG. 1 is a schematic perspective view illustrating a conventional three-dimensional rapid prototyping apparatus. The conventional three-dimensional rapid prototyping apparatus 1 comprises a construction platform 10, a construction chamber 11, a powder feeder 12, a movable platform 13 and a powder filtering mechanism 14. The construction chamber 11 and the powder feeder 12 are embedded in the construction platform 10. A printing module 15 is installed on the movable platform 13. Consequently, the printing module 15 is synchronously moved with the movable platform 13 back and forth. As the printing module 15 is moved with the movable platform 13 to a position over the construction chamber 11, the printing module 15 prints liquid binder or ink on the construction powder which is accommodated within the construction chamber 11. Consequently, a rapid prototyping process is performed. Moreover, the flying dust of the excess construction powder from the construction platform 10 is filtered by the powder filtering mechanism 14. The powder filtering mechanism 14 is located beside the construction platform 10. Conventionally, the powder filtering mechanism 14 comprises a fan 140, plural filters 141 and two coupling plates 142. By means of the coupling plates 142, the powder filtering mechanism 14 is fixed at a lateral side of the construction platform 10. Moreover, an opening 143 is defined by the two coupling plates 142 and the construction platform 10. The plural filters 141 are disposed within the opening 143. The fan 140 is behind the plural filters 141. During operation of the fan 140, negative pressure airflow is provided. Consequently, the flying dust of the excess construction powder from the construction platform 10 is inhaled into the opening 143 of the powder filtering mechanism 14. After the flying dust is filtered by the plural filters 141, the flying dust will not be exhausted out of the three-dimensional rapid prototyping apparatus 1. Consequently, the possibility of polluting the working environment by the flying dust will be reduced.
However, since the opening 143 is open to the construction platform 10, some problems possibly occur. For example, if the flying dust filtered by the filters 141 smells unpleasant, unpleasant odor may diffuse to the working environment. Moreover, due to the arrangement of the powder filtering mechanism 14 and the opening 143, it is difficult to collect and filter the flying dust at the corners of the three-dimensional rapid prototyping apparatus 1. In other words, the powder filtering mechanism 14 cannot effectively filter the flying dust and remove the unpleasant odor of the flying dust.
Therefore, there is a need of providing an improved powder filtering system for a rapid prototyping apparatus in order to overcome the above drawbacks.